text: /****************************************************************************
   *
   * ftbzip2.c
   *
   *   FreeType support for .bz2 compressed files.
   *
   * This optional component relies on libbz2.  It should mainly be used to
   * parse compressed PCF fonts, as found with many X11 server
   * distributions.
   *
   * Copyright (C) 2010-2021 by
   * Joel Klinghed.
   *
   * based on `src/gzip/ftgzip.c'
   *
   * This file is part of the FreeType project, and may only be used,
   * modified, and distributed under the terms of the FreeType project
   * license, LICENSE.TXT.  By continuing to use, modify, or distribute
   * this file you indicate that you have read the license and
   * understand and accept it fully.
   *
   */
  
  
  #include <freetype/internal/ftmemory.h>
  #include <freetype/internal/ftstream.h>
  #include <freetype/internal/ftdebug.h>
  #include <freetype/ftbzip2.h>
  #include FT_CONFIG_STANDARD_LIBRARY_H
  
  
  #include <freetype/ftmoderr.h>
  
  #undef FTERRORS_H_
  
  #undef  FT_ERR_PREFIX
  #define FT_ERR_PREFIX  Bzip2_Err_
  #define FT_ERR_BASE    FT_Mod_Err_Bzip2
  
  #include <freetype/fterrors.h>
  
  
  #ifdef FT_CONFIG_OPTION_USE_BZIP2
  
  #define BZ_NO_STDIO /* Do not need FILE */
  #include <bzlib.h>
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****           B Z I P 2   M E M O R Y   M A N A G E M E N T         *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
    /* it is better to use FreeType memory routines instead of raw
       'malloc/free' */
  
    typedef void *(* alloc_func)(void*, int, int);
    typedef void (* free_func)(void*, void*);
  
    static void*
    ft_bzip2_alloc( FT_Memory  memory,
                    int        items,
                    int        size )
    {
      FT_ULong    sz = (FT_ULong)size * (FT_ULong)items;
      FT_Error    error;
      FT_Pointer  p  = NULL;
  
  
      (void)FT_QALLOC( p, sz );
      return p;
    }
  
  
    static void
    ft_bzip2_free( FT_Memory  memory,
                   void*      address )
    {
      FT_MEM_FREE( address );
    }
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****              B Z I P 2   F I L E   D E S C R I P T O R          *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
  #define FT_BZIP2_BUFFER_SIZE  4096
  
    typedef struct  FT_BZip2FileRec_
    {
      FT_Stream  source;         /* parent/source stream        */
      FT_Stream  stream;         /* embedding stream            */
      FT_Memory  memory;         /* memory allocator            */
      bz_stream  bzstream;       /* bzlib input stream          */
  
      FT_Byte    input[FT_BZIP2_BUFFER_SIZE];  /* input read buffer  */
  
      FT_Byte    buffer[FT_BZIP2_BUFFER_SIZE]; /* output buffer      */
      FT_ULong   pos;                          /* position in output */
      FT_Byte*   cursor;
      FT_Byte*   limit;
  
    } FT_BZip2FileRec, *FT_BZip2File;
  
  
    /* check and skip .bz2 header - we don't support `transparent' compression */
    static FT_Error
    ft_bzip2_check_header( FT_Stream  stream )
    {
      FT_Error  error = FT_Err_Ok;
      FT_Byte   head[4];
  
  
      if ( FT_STREAM_SEEK( 0 )       ||
           FT_STREAM_READ( head, 4 ) )
        goto Exit;
  
      /* head[0] && head[1] are the magic numbers;    */
      /* head[2] is the version, and head[3] the blocksize */
      if ( head[0] != 0x42  ||
           head[1] != 0x5A  ||
           head[2] != 0x68  )  /* only support bzip2 (huffman) */
      {
        error = FT_THROW( Invalid_File_Format );
        goto Exit;
      }
  
    Exit:
      return error;
    }
  
  
    static FT_Error
    ft_bzip2_file_init( FT_BZip2File  zip,
                        FT_Stream     stream,
                        FT_Stream     source )
    {
      bz_stream*  bzstream = &zip->bzstream;
      FT_Error    error    = FT_Err_Ok;
  
  
      zip->stream = stream;
      zip->source = source;
      zip->memory = stream->memory;
  
      zip->limit  = zip->buffer + FT_BZIP2_BUFFER_SIZE;
      zip->cursor = zip->limit;
      zip->pos    = 0;
  
      /* check .bz2 header */
      {
        stream = source;
  
        error = ft_bzip2_check_header( stream );
        if ( error )
          goto Exit;
  
        if ( FT_STREAM_SEEK( 0 ) )
          goto Exit;
      }
  
      /* initialize bzlib */
      bzstream->bzalloc = (alloc_func)ft_bzip2_alloc;
      bzstream->bzfree  = (free_func) ft_bzip2_free;
      bzstream->opaque  = zip->memory;
  
      bzstream->avail_in = 0;
      bzstream->next_in  = (char*)zip->buffer;
  
      if ( BZ2_bzDecompressInit( bzstream, 0, 0 ) != BZ_OK ||
           !bzstream->next_in                              )
        error = FT_THROW( Invalid_File_Format );
  
    Exit:
      return error;
    }
  
  
    static void
    ft_bzip2_file_done( FT_BZip2File  zip )
    {
      bz_stream*  bzstream = &zip->bzstream;
  
  
      BZ2_bzDecompressEnd( bzstream );
  
      /* clear the rest */
      bzstream->bzalloc   = NULL;
      bzstream->bzfree    = NULL;
      bzstream->opaque    = NULL;
      bzstream->next_in   = NULL;
      bzstream->next_out  = NULL;
      bzstream->avail_in  = 0;
      bzstream->avail_out = 0;
  
      zip->memory = NULL;
      zip->source = NULL;
      zip->stream = NULL;
    }
  
  
    static FT_Error
    ft_bzip2_file_reset( FT_BZip2File  zip )
    {
      FT_Stream  stream = zip->source;
      FT_Error   error;
  
  
      if ( !FT_STREAM_SEEK( 0 ) )
      {
        bz_stream*  bzstream = &zip->bzstream;
  
  
        BZ2_bzDecompressEnd( bzstream );
  
        bzstream->avail_in  = 0;
        bzstream->next_in   = (char*)zip->input;
        bzstream->avail_out = 0;
        bzstream->next_out  = (char*)zip->buffer;
  
        zip->limit  = zip->buffer + FT_BZIP2_BUFFER_SIZE;
        zip->cursor = zip->limit;
        zip->pos    = 0;
  
        BZ2_bzDecompressInit( bzstream, 0, 0 );
      }
  
      return error;
    }
  
  
    static FT_Error
    ft_bzip2_file_fill_input( FT_BZip2File  zip )
    {
      bz_stream*  bzstream = &zip->bzstream;
      FT_Stream   stream    = zip->source;
      FT_ULong    size;
  
  
      if ( stream->read )
      {
        size = stream->read( stream, stream->pos, zip->input,
                             FT_BZIP2_BUFFER_SIZE );
        if ( size == 0 )
        {
          zip->limit = zip->cursor;
          return FT_THROW( Invalid_Stream_Operation );
        }
      }
      else
      {
        size = stream->size - stream->pos;
        if ( size > FT_BZIP2_BUFFER_SIZE )
          size = FT_BZIP2_BUFFER_SIZE;
  
        if ( size == 0 )
        {
          zip->limit = zip->cursor;
          return FT_THROW( Invalid_Stream_Operation );
        }
  
        FT_MEM_COPY( zip->input, stream->base + stream->pos, size );
      }
      stream->pos += size;
  
      bzstream->next_in  = (char*)zip->input;
      bzstream->avail_in = size;
  
      return FT_Err_Ok;
    }
  
  
    static FT_Error
    ft_bzip2_file_fill_output( FT_BZip2File  zip )
    {
      bz_stream*  bzstream = &zip->bzstream;
      FT_Error    error    = FT_Err_Ok;
  
  
      zip->cursor         = zip->buffer;
      bzstream->next_out  = (char*)zip->cursor;
      bzstream->avail_out = FT_BZIP2_BUFFER_SIZE;
  
      while ( bzstream->avail_out > 0 )
      {
        int  err;
  
  
        if ( bzstream->avail_in == 0 )
        {
          error = ft_bzip2_file_fill_input( zip );
          if ( error )
            break;
        }
  
        err = BZ2_bzDecompress( bzstream );
  
        if ( err == BZ_STREAM_END )
        {
          zip->limit = (FT_Byte*)bzstream->next_out;
          if ( zip->limit == zip->cursor )
            error = FT_THROW( Invalid_Stream_Operation );
          break;
        }
        else if ( err != BZ_OK )
        {
          zip->limit = zip->cursor;
          error      = FT_THROW( Invalid_Stream_Operation );
          break;
        }
      }
  
      return error;
    }
  
  
    /* fill output buffer; `count' must be <= FT_BZIP2_BUFFER_SIZE */
    static FT_Error
    ft_bzip2_file_skip_output( FT_BZip2File  zip,
                               FT_ULong      count )
    {
      FT_Error  error = FT_Err_Ok;
  
  
      for (;;)
      {
        FT_ULong  delta = (FT_ULong)( zip->limit - zip->cursor );
  
  
        if ( delta >= count )
          delta = count;
  
        zip->cursor += delta;
        zip->pos    += delta;
  
        count -= delta;
        if ( count == 0 )
          break;
  
        error = ft_bzip2_file_fill_output( zip );
        if ( error )
          break;
      }
  
      return error;
    }
  
  
    static FT_ULong
    ft_bzip2_file_io( FT_BZip2File  zip,
                      FT_ULong      pos,
                      FT_Byte*      buffer,
                      FT_ULong      count )
    {
      FT_ULong  result = 0;
      FT_Error  error;
  
  
      /* Reset inflate stream if we're seeking backwards.        */
      /* Yes, that is not too efficient, but it saves memory :-) */
      if ( pos < zip->pos )
      {
        error = ft_bzip2_file_reset( zip );
        if ( error )
          goto Exit;
      }
  
      /* skip unwanted bytes */
      if ( pos > zip->pos )
      {
        error = ft_bzip2_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
        if ( error )
          goto Exit;
      }
  
      if ( count == 0 )
        goto Exit;
  
      /* now read the data */
      for (;;)
      {
        FT_ULong  delta;
  
  
        delta = (FT_ULong)( zip->limit - zip->cursor );
        if ( delta >= count )
          delta = count;
  
        FT_MEM_COPY( buffer, zip->cursor, delta );
        buffer      += delta;
        result      += delta;
        zip->cursor += delta;
        zip->pos    += delta;
  
        count -= delta;
        if ( count == 0 )
          break;
  
        error = ft_bzip2_file_fill_output( zip );
        if ( error )
          break;
      }
  
    Exit:
      return result;
    }
  
  
  /***************************************************************************/
  /***************************************************************************/
  /*****                                                                 *****/
  /*****               B Z   E M B E D D I N G   S T R E A M             *****/
  /*****                                                                 *****/
  /***************************************************************************/
  /***************************************************************************/
  
    static void
    ft_bzip2_stream_close( FT_Stream  stream )
    {
      FT_BZip2File  zip    = (FT_BZip2File)stream->descriptor.pointer;
      FT_Memory     memory = stream->memory;
  
  
      if ( zip )
      {
        /* finalize bzip file descriptor */
        ft_bzip2_file_done( zip );
  
        FT_FREE( zip );
  
        stream->descriptor.pointer = NULL;
      }
    }
  
  
    static unsigned long
    ft_bzip2_stream_io( FT_Stream       stream,
                        unsigned long   offset,
                        unsigned char*  buffer,
                        unsigned long   count )
    {
      FT_BZip2File  zip = (FT_BZip2File)stream->descriptor.pointer;
  
  
      return ft_bzip2_file_io( zip, offset, buffer, count );
    }
  
  
    FT_EXPORT_DEF( FT_Error )
    FT_Stream_OpenBzip2( FT_Stream  stream,
                         FT_Stream  source )
    {
      FT_Error      error;
      FT_Memory     memory;
      FT_BZip2File  zip = NULL;
  
  
      if ( !stream || !source )
      {
        error = FT_THROW( Invalid_Stream_Handle );
        goto Exit;
      }
  
      memory = source->memory;
  
      /*
       * check the header right now; this prevents allocating unnecessary
       * objects when we don't need them
       */
      error = ft_bzip2_check_header( source );
      if ( error )
        goto Exit;
  
      FT_ZERO( stream );
      stream->memory = memory;
  
      if ( !FT_QNEW( zip ) )
      {
        error = ft_bzip2_file_init( zip, stream, source );
        if ( error )
        {
          FT_FREE( zip );
          goto Exit;
        }
  
        stream->descriptor.pointer = zip;
      }
  
      stream->size  = 0x7FFFFFFFL;  /* don't know the real size! */
      stream->pos   = 0;
      stream->base  = 0;
      stream->read  = ft_bzip2_stream_io;
      stream->close = ft_bzip2_stream_close;
  
    Exit:
      return error;
    }
  
  #else  /* !FT_CONFIG_OPTION_USE_BZIP2 */
  
    FT_EXPORT_DEF( FT_Error )
    FT_Stream_OpenBzip2( FT_Stream  stream,
                         FT_Stream  source )
    {
      FT_UNUSED( stream );
      FT_UNUSED( source );
  
      return FT_THROW( Unimplemented_Feature );
    }
  
  #endif /* !FT_CONFIG_OPTION_USE_BZIP2 */
  
  
  /* END */
  